Runway Overrun Risk & Stopping Margin Analyzer
Simulate transport-category aircraft landing ground roll deceleration, contaminated runway braking action (TALPA RWYCC), dynamic hydroplaning limits, and overrun excursion velocities across worldwide runways.
Deceleration Trajectory & Runway Layout (Top-Down Profile)
Deceleration & Aerodynamic Forces
| Aircraft Gross Mass | 305,000 lbs (138,345 kg) |
| Touchdown Ground Speed ($V_{td}$) | 154 kts (260 ft/s) |
| Effective Wheel Braking Friction ($\mu$) | 0.14 (Contaminated Wet) |
| Peak Anti-Skid Brake Force | 38,430 lbf |
| Peak Reverse Thrust Force | 0 lbf (De-selected) |
| Avg Deceleration Rate | -4.52 ft/s² (0.14 G) |
Regulatory Compliance & Standards
| FAA TALPA 15% Factor Buffer | 10,789 ft (Exceeds LDA) |
| Touchdown Air Distance | 1,850 ft (Long landing) |
| Ground Braking Roll | 7,532 ft |
| Kinetic Energy at Threshold End | 39.2 MJ (Overrun collision hazard) |
| EMAS Capture Status | No EMAS Available |
| Braking Action Assessment | POOR (RWYCC 2) |
Aviation Overrun Dynamics & TALPA Framework
Runway excursions account for over 25% of all commercial aviation accidents worldwide. Under the FAA's Takeoff and Landing Performance Assessment (TALPA) and ICAO's Global Reporting Format (GRF), runway conditions are categorized into Runway Condition Codes (RWYCC 0 through 6).
When standing water (>3mm) is present, tire hydrodynamic pressure creates dynamic hydroplaning at the critical velocity $V_p \approx 9 \sqrt{P_{psi}}$. During hydroplaning, wheel anti-skid friction drops near zero, and the aircraft relies almost exclusively on aerodynamic drag and reverse thrust until decelerating below $V_p$.
Contributing Overrun Multipliers
A 5-knot tailwind increases landing distance by ~15% on dry runways, but can extend stopping distances by over 35% on wet or contaminated runways. Touching down 1,000 feet beyond the standard 1,000-ft aimpoint consumes critical paved buffer before brakes can even be actuated.
Safety best practices mandate executing an immediate go-around if touchdown cannot be established within the designated Touchdown Zone (TDZ).
How does this calculator model physical deceleration forces?
The simulator integrates aircraft deceleration step-by-step ($dt = 0.05\text{ s}$) using four simultaneous forces:
1. Tire Braking Force: $F_b = \mu(v) \cdot (W - L(v))$, where $\mu$ accounts for RWYCC rating and dynamic hydroplaning decay when speed exceeds Horne's formula ($9 \sqrt{P_{psi}}$). Lift $L(v)$ is significantly reduced if ground spoilers deploy.
2. Aerodynamic Drag: $F_d = \frac{1}{2} \rho v_{air}^2 S C_D$, varying quadratically with true airspeed.
3. Reverse Thrust: $F_{rev}$, which is highly effective above 80 knots and throttled back toward idle below 60 knots to prevent engine debris ingestion.
4. Runway Slope Gravity Component: $F_g = W \sin(\theta)$, aiding deceleration on uphill slopes and extending ground roll on downhill gradients.
What is an EMAS (Engineered Materials Arresting System)?
An EMAS is a bed of cellular cement blocks placed at the end of a runway that crushes reliably under the weight of an overrunning aircraft, exerting predictable drag on the landing gear to decelerate and safely arrest the plane with minimal structural damage.
What is the difference between Unfactored and Factored Landing Distance?
Unfactored Landing Distance represents the absolute physical distance required to bring the airplane to a complete stop under test conditions. Factored Landing Distance Required applies regulatory safety multipliers (typically 1.15 for in-flight assessment under TALPA, or 1.67 for pre-dispatch planning) to protect against normal piloting variations, wind gusts, and friction variations.